1. Field of the Invention
The present invention relates to the general technical field of agricultural machinery. The invention relates to a distribution box for a single-seeder with a distribution disc provided with radial grooves that are regularly spaced apart and open on the periphery of said disc, said disc being rotatably mounted on a horizontal axis and separating a seed reservoir from a suction device such that the seeds are picked up from the reservoir by said disc via the air flow by negative pressure and are held over at least part of their angular travel until they are expelled from a discharge opening.
2. Description of the Related Art
Such a distribution box for a single-seeder is described in application DE 10 2008 037 397 A1. This distribution box comprises a rotary planar disc mounted on a horizontal axis. The disc selects seeds owing to an air flow making it possible to suck and hold the seed over part of its rotation. To that end, it has outwardly open radial grooves. The diameter of the grooves is identical over its entire length and has a size smaller than that of the seeds. Thus, the seeds are sucked, then held on the grooves by depression. During the rotation of the disc, the seeds are gradually brought toward the periphery of the disc, and therefore to the opening of the groove to be released. Distributing calibrated seeds with a regular shape using such a disc makes it possible to obtain good results. The choice of the disc, with a width of the grooves adapted to the size of the seeds, is easier, since the batch of seeds is homogenous. The sorted seeds better adapt to the dimensions of the grooves, and the number of deficiencies or duplications is very low.
However, when the shape of the seeds is irregular or unsuitable, the disc, via the grooves, does not manage to remove the seeds from the reservoir or two seeds are inserted, which leads to more deficiencies and/or duplications. The precision of the sowing is therefore altered.
Furthermore, the presence of the cavity at the groove makes the discharge of the seeds more difficult, since the seed is too engaged in the groove. The seeds do not slide over the groove regularly, and consequently the spacing between the seeds in the furrow is deteriorated.